Parameter Identity Repair — Unreal 5 Material Parameter GUID Collisions, Found and Fixed
An Unreal Engine 5 plugin from Core Systems Asset Factory. Made with Unreal Engine. Paid.
Parameter Identity Repair — Unreal 5 Material Parameter GUID Collisions, Found and Fixed is an Unreal Engine 5 plugin for Unreal Engine, paid.
Its title or description names Unreal Engine 5.
Drag Roughness Scale in a material instance and watch Metallic Scale move with it. That is not a UI bug. Those two parameters are sharing one hidden identity, and the engine cannot tell them apart. Every material parameter carries an ExpressionGUID. You never see it, and material instances bind their overrides to it rather than to the parameter's name.
Duplicate a material function and the copy keeps the original's GUIDs. That is the ordinary way anyone builds a family of materials, and it is the ordinary way this defect enters a project. It is not an oversight either. UMaterialExpression::PostDuplicate says so in the engine source: "We do not force a guid regen here because this function is used when the Material Editor makes a copy of a material to edit.
If we forced a GUID regen, it would cause all of the guids for a material to change everytime a material was edited." Epic made a reasonable trade. Nothing in the editor cleans up after it. Across the whole engine the only places that mint a fresh parameter identity are node creation and paste: there is no command, no menu item and no scripting function that repairs a collision once it exists.
AI disclosure, as the store page states it: AI Assisted, Code, Graphics
Paid · Get it on itch.io. Files, screenshots and the full description are on the store page.